Alpha-aryl-n-lower alkyl nitronecontaining compositions useful as anti-microbial agents

ABSTRACT

NOVEL COMPOSITIONS COMPRISING AN INERT DILUENT OR CARRIER AND AN ALPHA-ARYL-N-LOWER ALKYL NITRONE ARE DESCRIBED. THE COMPOSITTIONS ARE ADVANTAGEOUS IN THAT THEY HAVE ACTIVITY OVER A WIDE SPECTRUM OF PHYTOPATHOGENIC MICRO-ORGANISMS WHILE, AT THE SAME TIME, THEY ARE NOT PHYTOTOXIC TO SELECTED CROP AND ORNAMENTAL PLANTS. ALSO DESCRIBED ARE PROCESSES FOR CONTROLLING PLANT PATHOGENS IN SOIL BY TREATMENT OF THE SOIL OR SEEDS WHICH ARE TO BE INCORPORATED IN SOIL.

United States Patent 3,740,441 ALPHA-ARYL-N-LOWER ALKYL NITRONE-CONTAINING COMPOSITIONS USEFUL AS ANTI-MICROBIAL AGENTS Kenneth P.Dorsehner, and James A. Albright, Jacksonville, Fla., assignors to SCMCorporation, Cleveland, Ohio No Drawing. Filed May 3, 1971, Ser. No.139,867 Int. Cl. A01n 9/20, 21/00 US. Cl. 424-327 7 Claims ABSTRACT OFTHE DISCLOSURE Novel compositions comprising an inert diluent or carrierand an alpha-aryl-N-lower alkyl nitrone are described. The compositionsare advantageous in that they have activity over a wide spectrum ofphytopathogenic micro-organisms while, at the same time, they are notphytotoxic to selected crop and ornamental plants. Also described areprocesses for controlling plant pathogens in soil by treatment of thesoil or seeds which are to be incorporated in soil.

BACKGROUND OF THE INVENTION The invention relates to novel compositionswhich have been found to be particularly effective againstsoilinhabiting pathogenic micro-organisms, especially fungi. Thecompositions are useful in that when applied to soils infested withphyto-pathogenic micro-organisms as amendments to the soil, or when theyare applied to seeds before planting, they are highly effective asprotective agents and permit normal growth and development of thedesired plant species.

The lack of phytotoxicity of these compositions permits treatment of theseeds of plant species, the seeds of which are normally highly sensitiveto the conventional mercurial fungicides; for example, the seeds of cropplants such as corn and peanuts. These compositions were highlybeneficial since these same compositions control plant pathogensnormally controlled with mercurial fungicides.

THE PRIOR ART Alpha-aryl-N-lower alkyl nitrones are known compounds andhave been used as intermediates in synthetic organic reactions.Compounds falling within this class often undergo molecularrearrangement when exposed to long wave ultraviolet light. However,utility of this class of compounds in pesticidal applications has not,to the best of applicants knowledge and belief, been known before thepresent invention.

The closest prior art known to the applicants including the authorsname, journal, and Chemical Abstracts reference of the prior artpublication is set forth in form PO-l082 (ll-69) attached hereto.

In its broadest aspect, the invention provides a composition comprising:

(a) An inert carrier, and

(b) An anti-microbially effective amount of an alphaaryl-N-lower alkylnitrone where the alpha-aryl group is substituted or unsubstituted.

In an advantageous embodiment the invention provides a compositioncomprising:

(a) An inert carrier, and

(b) An anti-microbially effective amount of a compound of the formula:

31 O Yx-At- 17:13-11 where Y is a substituent selected from the groupconsisting of halogen, hydroxyl, lower alkoxy, lower alkyl, and

nitro-, n is an integer of from 0 to 5, Ar is phenyl, and A is loweralkyl. Such compositions, when used to contact soils contaminated withmicro-organisms which are pathogenic to cultivated plants or when usedto contact seeds of such plants prior to planting the seeds, effectivelyprevent substantial injury to or killing of plants which are susceptibleto attack by such soil-inhabiting micro-organisms, especially fungi.

The compositions of this invention have been found to be effectiveagainst a wide spectrum of plant pathogens which damage or kill cropplants such as, for example, cotton, corn, oats, peas, peanuts,soybeans, sugar beets, beets, onions, melons, and the like.

Examples of species of genera which are pathogenic to plants and whichare controlled or killed by the compositions of this invention includespecies of: Rhizoctonia, Thielaviopsis, Pythium, Fusarium, lsclerotium,Aphanomyces, Urocystis, Pyrenochaeta, Glomerella, Helminthosporium,Rhizopus, Aspergillus, Phoma, Ustillago, and the like. Various speciesof the above-recited genera of organisms are known to cause pre-emergentand/ or postemergent diseases in or on one or more of the abovementionedcrop plants, sometimes causing complete crop destruction and almostalways resulting in a severe reduction in crop yield.

The anti-microbial activity of the compositions of this invention isunexpected because most pesticidal agents which are incorporated insoils or on seeds are active against a relatively narrow spectrum ofplant pathogens and are frequently phytotoxic at the high dosagerequired for effective disease control. The compositions of the presentinvention are substantially non-phytotoxic at levels at which theytotally eliminate or control a wide variety of plant pathogens.

In another aspect the invention provides a process which comprisescontacting soils containing micro-organisms which are pathogenic tocultivated plants with from about 0.6 to about pounds per acre of thecomposition falling within the scope of this invention. As will beevident hereinafter from the specific examples, compositions containingcompounds falling within the scope of the above-described formulaeffectively kill or control the growth of a broad spectrum ofsoil-inhabiting micro-organisms which are pathogenic to plants withoutsubstantially adversely affecting the growth of the plant and ultimatecrop yield.

In still another aspect, the invention provides a process whichcomprises contacting at least a portion of the surfaces of seeds ofcultivated plants with from about 0.2 to about 4 weight percent, basedon the weight of the seeds, of the compositions of this invention,thereby rendering the seeds resistant to attack by soil-inhabitingmicro-organisms which are pathogenic to the seeds or young plants.

When seeds are planted in soils, pathogenic microorganisms often attackthe seed embryo and injure or destroy it before it can grow. Also andmore often, the micro-organisms attack the plant embryo just after thegermination of the seed, killing it or severely impairing its growth anddevelopment.

It has presently been found that the compositions of this invention,when applied to at least a portion of the surfaces of seeds, will renderthem resistant to attack by soil-inhabiting micro-organisms which arepathogenic to the seeds and/or plants thereby rendering the seed and/ orthe plant which develops from the seed resistant to attack by suchmicro-organisms. The compounds set forth as one component ofcompositions falling Within the scope of this invention are substitutedor unsubstituted alphaaryl-N-lower alkyl nitrones. Where the aryl groupis unsubstituted, the compound is an alpha-phenyl-N-lower alkyl nitrone.

The lower alkyl group attached to the nitrogen atom in thealpha-aryl-N-lower alkyl nitrones advantageously contains from 1 to 4carbon atoms, and preferably between 1 and 2 carbon atoms for economicreasons.

Specific examples of compounds falling within the scope of compositionscontaining compounds with unsubstituted aryl groups are as follows:

alpha-phenyl-N-methyl nitrone, alpha-phenylN-ethyl nitrone,alpha-phenyl-N-propyl nitrone, alpha-phenyl-N-butyl nitrone,

as well as the analogs of such propyl and butyl nitrones.

Compositions containing compounds wherein the aryl groups contains oneor more substituents are those in the hereinbefore-designated formula; Yis a substituent selected from the group consisting of halogen,hydroxyl, lower alkoxy, lower alkyl, and nitro, and n is an integer offrom 1 to 5.

Compounds wherein Y is a halogen atom include those containing chlorine,bromine, and fluorine atoms as substituents on the aryl group.

In compounds where Y is a halogen atom, 11 can be an integer of from oneto five. Compounds which have been found to be particularly advantageouswhere Y is a halogen atom and n is one, include:

alpha-(2-chlorophenyl)-N-lower alkyl nitrone, where the lower alkylgroup contains from one to four carbon atoms;

al ha-(3-chlorophenyl)-N-lower alkyl nitrone; and

alpha-(4-chlorophenyl)-N-lower akyl nitrone, where the lower alkyl is asabove described.

These compounds and their corresponding bromoand fluoroderivatives havebeen found to be effective fungicides when employed in the compositionsof this invention. Compositions in said compound where Y is a halogenatom and n is two include, for example, alpha-(2,4-dichlorophenyl)-N-lower alkykl nitrone; and alpha-(3,4-dichlorophenyl)-N-lower alkyl nitrone. Compositions containing thesecompounds and/or their corresponding bromoand fluoro-derivatives havealso been found to be fungicidally effective.

Another effective compound which had been found to provide anadvantageous composition is'one wherein Y is fluoroand n is five andspecifically is alpha- (pentafluorophenyD-N-lower alkyl nitrone.Although distinctly different compounds wherein Y is haloand n is aninteger of from one to five may be employed, the hereinbefore-designatedspecific compounds are generally preferred for economic reasons.

In the above compositions, compounds in which Y is a nitrosubstituenthave also been found to be useful, and in such compounds it is usuallyan integer of 1 or 2. Particularly active compositions are those whereinat least one of the following specific compounds are incorporated:

alpha-(2-nitrophenyl)-N-lower alkyl nitrone;alpha-(3-nitrophenyl)-N-lower alkyl nitrone;alpha-(4-nitrophenyl)-N-lower alkyl nitrone;alpha-(2,3-dinitrophenyl)-N-lower alkyl nitrone; andalpha-(2,4-dinitrophenyl)-N-lower alkyl nitrone.

The compositions can also contain compounds in which Y in the formula isa hydroxyl substituent and n is an integer of from 1 to 5. Of thesecompounds, those wherein n is 1 have been found preferable for economicreasons. Embodiments of such compounds are:

alpha-(2-hydroxy phenyl)-N-lower alkyl nitrone; alpha-(3-hydroxyphenyl)-N-lower alkyl nitrone; and alpha-(4-hydroxy phenyl)-Nlower alkylnitrone.

As noted hereinbefore, Y can also be a lower alkyl substituent and cannclude methyl ethyl propyl and sec-butyl or t-butyl, and alkylsubstituent can either be on the l, 2, or 3 positions of the phenylgroup.

Also, as previously noted, Y can be a lower alkoxy group includingmethoxy, ethoxy, propoxy, butoxy, etc., and such groups can be on the 1,2, or 3 positions of the phenyl group. Compositions containing compoundswhere Y is lower alkyl or lower alkoxy are usually those in which n is 1for economic reasons and for maximum fungicidal activity. However, n canbe an integer of from 1 to 5, and is usually an integer of from 1 to 3.

Preferred compositions have been found to be those containing one ormore of the classes of compounds set forth hereinbefore, since thesehave been found to be maximally effective and are substantially free ofphytotoxic activity.

It is to be understood, however, that almost any compound, if used insufliciently high concentrations, behaves as a foreign substance; and insuch circumstances will have adverse effects upon seeds or plants.However, con1- pounds falling within the scope of the formula of thecompositions of this invention generally are fungicidally effective atlevels far below those which are phytotoxic to crop plants.

The inert carrier or diluent which is employed in the compositions ofthis invention can be any carrier or diluent conventionally used in theagricultural pesticide art with the proviso that the carrier should beinert; that is, it should be incapable of undergoing a chemical reactionwith alpha-aryl-N-lower alkyl nitrone in the compositions and should notbe harmful to the plant or plants or the seeds thereof.

The carrier can be any one of a variety of organic and inorganic,liquid, solid, or semisolid carriers or carrier formulationsconventionally used in the soil treatment or seed treatment products.Examples of organic liquid carriers include volatile liquid aliphatichydrocarbons, such as pentane, hexane, heptane, octane, etc., and theiranalogs, as well as volatile liquid aromatic hydrocarbons such asbenzene, o-xylene, m-xylene, p-xylene, naphthylene, alpha-methylnaphthylene, beta-methyl naphthylene, etc.

In addition to the above-mentioned volatile liquid hydrocarbons, andoften used in conjunction therewith, the carrier can containconventional surfactants or emulsifying agents, such as, for example,nonionic surfactants embodied by an ethylene oxide condensate of analkyl phenol or an anionic surfactant embodied by an alkali metal saltof an alkyl benzene sulfonic acid. Such emulsifiers are used to permitthe compositions to be dispersed in and diluted with water for end-useapplication. Conventional volatile aromatic and aliphatic esters,aldehydes, and ketones may also be employed as liquid organic inertdiluents; and when so used, are usually in combination with theabove-mentioned aliphatic and aromatic hydrocarbons.

Solid carriers which can be employed in the compositions of thisinvention include finely divided inorganic carriers, such as siliceousminerals including clays; for example, bentonite, attapulgite, fullersearth, diatomaceous earth, kaolin, mica, talc, and finely dividedquartz. Other inorganic carriers which may be employed are syntheticallyprepared finely divided siliceous materials, such as silica aerogels andprecipitated and fume silicas.

Examples of finely divided solid organic materials include: powderedsolid, nonionic and anionic surfactants, starch flour, sawdust, casein,gelatin, and the like. The inert carrier, when solid, will usuallycontain a mixture of finely divided siliceous mineral, advantageously aclay, and one or more surfactants. The kind of inert carrier or diluentemployed will depend upon the end use of the composition and nature ofthe plathogenic organism which it is necessary or desirable to control.

By way of example, where it is desired to treat seeds, the carrier canbe a slurried dust or an adherent powder having the alpha-aryl-N-loweralkyl nitrone dispersed therein. On the other hand, where it is desiredto employ the composition to contact soils, the composition can be awettable powder, a liquid spray, or a granular formulation containingthe nitrones. Such composition may be applied to the soil directly ormay be further diluted with water and applied to the soils as liquid orsprays.

The amount of carrier employed in the compositions of this invention mayvary considerably depending upon the intended end use of thecomposition. When the composition is to be applied to soil thecomposition should be designed to contain that amount of material whichwill provide a fungicidally effective amount of composition, usuallyexpressed in pounds per acre of the active material; that is, thealpha-aryl-N-lower alkyl nitrone, to the soil. Further, where thecomposition is to consist of a Waterdispersible formulation which willbe further diluted with water for end-use purposes, smaller amounts ofinert carrier or diluent will be employed and the diluted composition isalso intended to be within the scope of this invention, although itcontains water in addition to the hereinbefore-defined inert carrier ordiluent. Where the surfaces of seeds are to be treated, a liquid slurryor a powdered composition may be employed and the powdered compositionused to dust at least a portion of the surface of the seeds, thecomposition will usually contain larger amounts of the nitronecompounds, then is the case where a liquid composition is used toatomize the materials onto the surface of the seeds.

For all uses, the compositions of this invention will contain from about0.5 to about 95 weight percent of at least one of the alpha-aryl-N-loweralkyl nitrones and from about 99.5 -to about 5 weight percent of theinert carrier or diluent.

In one of its embodiments, the invention provides a process whichcomprises contacting soils with from about :6 to about 100 pounds peracre broadcast of the compositions of this invention. Although soilswhich are infested with micro-organisms which are pathogenic tocultivated plants are usually contacted with the composition of thisinvention, soils which do not contain appreciable quantitles of suchmicro-organisms may be contacted with the compositions to prevent futureinfestation of the soil.

The contact of the soil can be effected in a variety of ways and willdepend upon whether the composition is in liquid or solid form. Wherethe composition is in liquid form, contact can be effected with aconventional spray apparatus such as those commonly employed in theagricultural pesticide field. If the composition is a finely dividedpulverulent granular solid, contact can be effected much in the same Wayas is employed when fertilizers are applied. In fact, the inert carriermay be a fertilizer as long as its components are inert with respect tothe compounds of the compositions of the present invention.

When the compositions of this invention are used to treat at least aportion of the seeds of cultivated plants, the method of contact of theseeds will also depend on whether the composition is in liquid orparticulate solid form. By way of example, if the composition is inliquid form, the material can be sprayed on the seeds which can then betumbled to provide an admixture of the composition with the seeds. Onthe other hand, if the material is in particulate form, the compositionmay be mixed with the seeds, preferably by tumbling for a timesufficient to insure intimate contact of the composition particles withthe seeds.

The amount of composition which may be employed to contact the soil canvary widely depending on the amount in kinds of plant pathogens whichare in the soils, as well as the type of soil to be treated. Generally,an amount varying in the range of from about 0.6 to about 100 pounds ofcomposition per acre broadcast will effectively control a Wide spectrumof soil microorganisms. If less than about 0.6 pound per acre isemployed, there is some danger that not all of the micro-organisms willbe killed. Although more than 100 pounds per acre may be employed, suchamounts are economically disadvantageous, and there exists some dangerinsofar as certain specific plants are concerned of the compositionsexerting mild phytotoxicity on the plants.

When seeds are to be contacted, the amount of composition employed willvary from about 0.2 to about 4 weight percent based on the weight of theseeds. The amount of composition employed will depend upon the size ofthe seeds and, therefore, the surface area thereof; and higher amountswill be employed when the size of the particular plant seed is small,the lower amounts being generally employed where the size of the plantseed is larger. If less than 0.2 weight percent of composition isemployed, there is some danger that the seeds will not be adequatelyprotected against attack by plant pathogens. If more than about 4percent composition is employed, there is some danger insofar as certainplant species are concerned that injury to the plant may occur duringthe germination of the seeds.

The following specific examples are intended to illustrate theinvention, but not to limit the scope thereof, parts and percentagesbeing by weight unless otherwise specified.

EXAMPLE 1 A portion of standard greenhouse soil was conventionallysterilized with methyl bromide and placed into 32 disposable4-inch-square by 6-inch-deep containers in an amount such that thecontainer was substantially filled with the soil. Thereafter, seven ofthe containers were inoculated with Pythium irregulwre by applying aculture of this fungus to the containers and mixing. Another separateset of seven containers was inoculated with Rhizoctonia solani using thesame procedure. A third set of seven containers was inoculated withSclerotz'um rolfsii and a fourth set of seven containers was inoculatedwith F umrium oxysporum. Thereafter, three of the seven containers whichhad been inoculated with Pythium irregulwre were treated with 100, '50,and 25 parts per million, basis the weight of the soil, ofalpha-(p-chlorophenyl)-N- methyl nitrone. Another set of threecontainers which had been inoculated with the Pythium irregulare funguswas treated with 100, 50, and 25 parts per million, respectively, basedon the weight of the soil, with a dispersion of l-chloro, 2-nitropropane, a commercially available fungicide sold under the trademark ofLanstan. The remaining single container remained untreated to serve as acontrol, anda sterilized uninoculated container served as an additionalcontrol.

Three of the containers which had been inoculated with the Rhizoctoniwsolani fungus were treated with 100, 50, and 25 parts per million,respectively, with alpha-(p-chlorophenyl)-N-methyl nitrone. A second setof three of the seven containers which had been inoculated with the Rhizoctoniw salami fungus were treated with 1 00, 50, and 25 parts permillion, respectively, of l-chloro, 2-nitro propane. The remainingsingle container remained untreated to serve as an additional control.

Three containers of the set of seven which had been inoculated with theSclerotium rolfsii fungus were treated with 100, 50, and 25 parts permillion, respectively, basis the weight of the soil, withalpha-(p-chlorophenyl)- N-methyl nitrone. A second set of three receivedtreatment with the standard material in identical dosages; e.g.,l-chloro, 2-nitro propane. Again, positive and negative controls; thatis, inoculated soil and sterile soil, were maintained. Three of the setof seven containers which had been inoculated with Fusarium oxysporumwere treated with 100, 50, and 25 parts per million, respectively, basisthe weight of the soil, of the alpha- (p-chlorophenyl)-N-methyl nitrone.Three of the set of seven which had been treated with the Fusariumoxysporum fungus were comparably treated with the standard l-chloro,Z-nitro propane as previously described.

The positive and negative controls were also maintained. Mycelial growthof the fungi was observed daily for 14 days, after which the surfacearea of the soil which was covered by mycelial growth was measured. Theresults showed that the alpha-(p-chlorophenyl)-N-methyl nitrone wasabout equal in controlling fungal growth of Sclerotium rolfsl'i andFusarium oxysporum to the standard l-chloro, 2-nitro propane at levelsgiven and was also about equal with respect to Pythium irregulare. Thenitrone had about the same eifectiveness as the standard control incontrolling Rhizoctonia solani.

When the same quantities of inoculated soils using the procedures abovedescribed are treated with alpha-(pchlorophenyl)-N-ethyl nitrone,alpha-(p-chlorophenyl)- N-propyl nitrone, alpha-(3chlorophenyl)-N-methyl nitrone, alpha-(p-bromophenyl)-Nmethyl nitrone,alpha-(Z-nitrophenyl) N-methyl nitrone,alpha-(2,3-dinitrophenyl)-N-ethyl nitrone, andalpha-(2-hydroxyphenyl)-N-ethy1 nitrone substantially the same resultsare obtained.

EXAMPLE 2 The soil sterilization and inoculation procedures of Example 1were repeated, except that nine instead of 32 containers were filledwith sterile greenhouse soil and inoculated with a culture of theorganism Pythium: irregulare. Just prior to the inoculation, English peaseeds were planted in each container. Thereafter, four of the ninecontainers were treated with 100, 50, 25, and 12.5 parts per million,respectively, based on the weight of the soil, withalpha-(p-chlorophenyl)-Nmethyl nitrone. Also, four of the containerswere treated with 100, 50, 25, and 12.5 parts per million, respectively,basedon the weight of the soil, with l-chloro, 2-nitro propane, thecommercial standard. One container of sterile soil was also planted withEnglish pea seeds as was an untreated container which had beeninoculated with the Pythium. irregulare fungus. After 14 days, none ofthe seeds planted in the untreated inoculated soil produced plants. Thesterile soil produced 95 percent of the plants from the seeds. Thealpha-(p-chlorophenyl)-N-methyl nitrone was equal to the sterilizedcontrol at 100 parts per million, and the commercial product wasphytotoxic at this level, in containers dosed at 50, 25, and 12.5 partsper million fungicide. In each instance, the alpha-(pchlorophenyl)-N-methyl nitrone and the commercial product, l-chloro,2-nitro propane, were substantially the same. When the above example isrepeated using alpha- (p-methoxyphenyl)-N-ethyl nitrone in place of thenitrone used in Example 2, similar results are obtained.

EXAMPLE 3 The soil sterilization and inoculation procedures described inExample 1 were repeated, except that 21 containers were used in place ofthe 32 containers used in Example 1. Seven of the containers wereinoculated with the fungus Rhizoctonia solani. When the set of seven wasinoculated with Sclerotium rolfsii and the third set of seven wasinoculated with F usarium oxysporum just prior to the fungusinoculation, the seven containers that had been inoculated withRhizoczonia solani were planted with 10 beet seeds in each container.The seven containers which had been inoculated with Sclerotium. rolfsiiwere planted with 10 cucumber seeds in each container, and the seventhat had been inoculated with Fusarium oxysporum were planted with 10tomato seeds in each container. Three of the containers which wereinoculated with Rhizoctonia solarzi were treated with 100, 5 0, and 25parts per million, basis the weight of the soil withalpha-(p-chlorophenyl)-N-methyl nitrone and three containers which hadbeen inoculated with Sclerolium rolfsii and three containers which hadbeen inoculated with Fusarium oxysporum were identically treated. Threecontainers which had been inoculated with Rhizoctonz'a solani receivedrespectively 100, 50, and 25 parts per million of the l-chloro, 2-nitropropane,

and three containers which had been inoculated with Sclerotium rolfsii,and three containers which had been inoculated with Fusarium oxysporumwere similarly treated. The seventh container in each set remaineduntreated and served as a control. The same amount of beet seeds wereplanted in a single container of sterile soil for each set and served asa control.

The test showed that the test compound was markedly superior to thecommercial standard and in controlling Fusarium oxysporum at inoculationlevels of 50 and 25 parts per million, respectively. The test compoundand the commercial standard were substantially ineffective incontrolling Sclerotium rolfsii and were partially elfective incontrolling Rhizoctonia solani. In fact, in the case of the Fusariumoxysporum, more tomato seeds permitted and produced healthy plants thanwas the case in the sterile soil container.

EXAMPLE 4 The sterilization and inoculation procedures described inExample 1 were repeated, except that seven containers were inoculatedwith cultures of Rhizoctonia solani. Just prior to inoculation, beetseeds which had been mixed with a formulation containing a mixture of 50percent alpha-(p-chlorophenyl)-N-methyl nitrone and 50 percentattapulgus clay. The treatment levels were 4, 2, and 1 ounce per bushel,respectively. Another portion of seeds were treated with the sameconcentrations of a formulation containing a mixture of 50 percentattapulgus clay and 50 percent N-trichloromethyl thio 4-cyclohexene,1,2- dicarboximide, a commercial fungicide sold under the trade name ofCaptan.

The results are set forth in the table below and show that the compoundalpha-(p-chlorophenyl)-N-methyl nitrone has substantially the sameeffectiveness at the two higher levels as the standard commercialproduct. At the lower level, the test product was slightly moreetfective than the standard.

TABLE I [Response of a soil fungus to chemicals applied as seedtreatments and the mfiuence of these applications on plant stand.Greenhouse] The soil cultures employed to inoculate the soils in theforegoing examples are prepared and maintained as folows:

' The test organisms are raised in sterile soil cultures to which hasbeen added 20 percent, by weight, of cornmeal. The soil to be used fordilution with the cornmeal is separately sterilized with methyl bromide.The pure culture soil used for test purposes is then prepared byadmixing 10 percent, by weight, of the test organisms inoculum withpercent, by weight, of sterilized soil. The soil is then aliquoted inS'O-gram quantities to three replicated containers. Such soil is treatedwith a chemical by drenching each container with 10 ml. of the nitroneor standard. The chemical concentration is so adjusted to make 10 ml.quantities give a dosage of parts per million, basedon the weight of thesoil.

In the foregoing examples, the following compounds have been evaluatedand substantially the same results were obtained as those specificiallyset forth in the examples:

alpha-(p-hydroxyphenyl)-Nmethy1 nitrone alpha-(p-hydroxyphenyl)-N-ethylnitrone alpha-(p-hydroxyphenyl)-N-n-propyl nitrone alpha-(p-hydroxyphenyl)-N-n-butyl nitrone alpha-(p-methoxyphenyD-N-methylnitrone alpha- (pethoxyphenyl -N-methyl nitrone alpha-(p-N-propoxyphenyl) -N-methyl nitrone alpha- (p-nitrophenyl -N-methy1nitrone alpha- (p-nitrophenyl)-N-ethyl nitronealpha-(1,3-dinitrophenyl)-N-methy1 nitrone alpha- (p-methylphenyl)-N-methyl nitrone alpha- (p-ethylphenyl)-N-methyl nitrone.

What is claimed is:

wherein Y is a substituent selected from the group consisting of chloro,bromo, fluoro, hydroxyl, C alkyl, C

alkoxy, and nitro; AI is phenyl; A is C alkyl; and n 2 2. The process ofclaim 1 wherein Y is chloro, bromo .3. The process of claim 1 whereinthe nitrone is a-(pchlorophenyl)-N-methyl nitrone.

4. The process of claim 1 wherein Y is nitro.

5. The process of claim 1 wherein Y is hydroxyl.

6. The process of claim 1 wherein Y is C alkoxy. 7. The process of claim1 wherein Y is C alkyl.

References Cited FOREIGN PATENTS 7/1968 Japan 424- 327 OTHER REFERENCESBerichte, 57B, pp. 2082-85, 1924.

Chemical Abstracts, vol. 51, item 7343b, 1957. Bull. Chem. Soc., Japan,vol. 35, pp. 555-62, 1962. Chemical Abstracts, vol. 59, item 3808g,1963.

Acta Chem. Scand., vol. 17, No. 7, pp. 2138-39, 1963. Bull. Chem. Soc.Japan, vol. 36, pp. 1552-63, 1963.

ALBERT T. MEYERS, Primary Examiner D. ROBINSON, Assistant Examiner US.Cl. X.R.

